Heat sink

ABSTRACT

A heat sink includes a first fin assembly including a number of first fins, and a second fin assembly including a number of second fins. The second fin assembly can be retracted into the first fin assembly to reduce volume of the heat sink when packing the heat sink, and the second fin assembly can be extend out of the first fin assembly to increase volume of the heat sink when using the first fin assembly for heat dissipation.

BACKGROUND

1. Technical Field

The disclosure relates to a heat sink.

2. Description of Related Art

Central processing units (CPUs) in computers have been developed to be more powerful. Therefore, heat sinks are made ever bigger to dissipate the increased amount of heat produced by the more powerful CPUs. However, larger heat sinks mean higher cost in packing and transporting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an embodiment of a heat sink.

FIG. 2 is a front view of the heat sink of FIG. 1.

FIG. 3 is similar to FIG. 1, but showing the heat sink in a different state.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 3, an embodiment of a heat sink 10 includes a base 20, a heat pipe 40, a first fin assembly 60, and two second fin assemblies 80.

The base 20 is used to contact with a heat generating device (not shown), such as a central processing unit, for example, and absorb heat generated by the heat generating device.

The heat pipe 40 is U-shaped and includes a first shaft 41, and two second shafts 42. The first shaft 41 is inserted into the base 20 with opposite ends of the first shaft 41 extending outside the base 20. The second shafts 42 perpendicularly extend from the opposite ends of the first shaft 41 towards a same direction, respectively. Each second shaft 42 has a round-shaped cross section.

The first fin assembly 60 includes a plurality of parallel first fins 61. Two through holes 600 are defined in each first fin 61 corresponding to the second shafts 42, where one of the through holes 600 is adjacent to a first end of the first fin 61, and the other one of the through holes 600 is adjacent to a second end opposite to the first end of the first fin 61. The second shafts 42 are inserted in the corresponding through holes 600 to connect the plurality of first fins 61 together to fix the first fin assembly 60.

The second fin assemblies 80 are rotatably mounted to the second shafts 42, respectively. Each second fin assembly 80 includes a plurality of parallel second fins 82. Each second fin 82 defines a rounded pivot hole (not labeled) engaging with the corresponding second shaft 42. Each second fin assembly 80 is rotatably mounted to the corresponding second shaft 42 via the plurality of second fins 82 strung by the corresponding second shaft 42, wherein the second fins 82 are located between adjacent first fins 61 respectively, so as to be staggered with the first fins 61. Each second fin assembly 80 further includes an operating bar 84 mounted to corresponding sides of the plurality of second fins 82.

The operating bar 84 of each second fin assembly 80 can be operated to rotate the second fin assembly 80 relative to the corresponding second shaft 42 of the heat pipe 40. When the heat sink 10 needs to be packed and transported, the second fin assemblies 80 can be rotated to retract into the first fin assembly 60, to reduce volume of the heat sink 10 (shown as in FIGS. 1 and 2). When the heat sink 10 is required to dissipate heat for a heat generating device, the second fin assemblies 80 can be rotated to extend out of the first fin assembly 60, to increase volume of the heat sink 10 (shown as in FIG. 3).

In other embodiments, one of the second fin assembly 80 may be omitted.

In other embodiments, the rounded pivot holes of the second fins 82 of each second fin assembly 60 may instead be elongated guiding holes, while the round-shaped cross section of each second shaft 42 may instead be rectangular. Thus, the second fin assemblies 80 can be slid relative to the first fin assembly 60 via the second shafts 42 sliding along the corresponding guiding holes, so as to extend out of or retract into the first fin assembly 60.

It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat sink comprising: a base for absorbing heat generated by a heat generating device; a heat pipe connected to the base; a first fin assembly fixed to the heat pipe, the first fin assembly comprising a plurality of parallel first fins; and at least one second fin assembly rotatably mounted to the heat pipe, each of the at least one second fin assembly comprising a plurality of parallel second fins; wherein the second fins are received between adjacent first fins respectively, and the second fins are able to be rotated out of the corresponding adjacent first fins via rotation of the at least one second fin assembly.
 2. The heat sink of claim 1, wherein an operating bar is mounted to the second fin assembly, the second fin assembly able to be rotated via operating the operating bar.
 3. The heat sink of claim 1, wherein the at least one second fin assembly comprises two, the heat pipe comprises a first shaft and two second shaft perpendicularly extending from opposite ends of the first shaft respectively, the first shaft is inserted into the base, the first fin assembly is fixed to the second shafts, and the second fin assemblies are mounted to the second shafts respectively.
 4. The heat sink of claim 1, wherein a cross section of each of the second shafts is rounded.
 5. A heat sink comprising: a base for absorbing heat generated by a heat generating device; a heat pipe connected to the base; a first fin assembly fixed to the heat pipe; and a second fin assembly movably mounted to the heat pipe; wherein the first fin assembly comprises a plurality of first fins, the second fin assembly comprises a plurality of second fins, and the first fins and the second fins are staggered and parallel with each other; wherein the second fin assembly is able to be move between a first position and a second position, in the first position the plurality of second fins are received among the plurality of first fins, and in the second position the plurality of second fins extend out of the plurality of first fins.
 6. The heat sink of claim 5, wherein an operating bar is mounted to the second fin assembly, the second fin assembly able to be moved via operating the operating bar.
 7. The heat sink of claim 5, wherein the heat pipe comprises a first shaft and a second shaft perpendicularly extending from the first shaft, the first shaft is inserted into the base, the first fin assembly is fixed to the second shaft, and the second fin assembly is movably mounted to the second shaft.
 8. The heat sink of claim 7, wherein the second fin assembly is rotatably mounted to the second shaft.
 9. The heat sink of claim 8, wherein a cross section of the second shaft is rounded.
 10. A heat sink comprising: a base for absorbing heat generated by a heat generating device; a heat pipe comprising a first shaft and second shaft extending from the first shaft, the first shaft connected to the base; a first fin assembly fixed to the second shaft, the first fin assembly comprising a plurality of parallel first fins; and a second fin assembly movably mounted to the second shaft, each of the at least one second fin assembly comprising a plurality of parallel second fins; wherein the second fins are received between adjacent first fins respectively, and the second fins are able to be moved out of the corresponding adjacent first fins via moving the at least one second fin assembly along a plane perpendicular with the second shaft.
 11. The heat sink of claim 10, wherein an operating bar is mounted to the second fin assembly, the second fin assembly able to be moved via operating the operating bar.
 12. The heat sink of claim 10, wherein the second fin assembly is rotatably mounted to the second shaft.
 13. The heat sink of claim 12, wherein a cross section of the second shaft is rounded. 